1. Field of the Invention
The present invention relates to a ceiling type air conditioner, which is installed to an indoor ceiling of a building, so as to purify the indoor air and properly adjust the temperature and humidity of the indoor air to be maintained at a desired level, thereby providing more pleasant life environment. More particularly, the present invention relates to an improved structure of a turbo fan, an element employed in a ceiling type air conditioner so as to generate fluid flow, which improvement enables the turbo fan to be employed in the air conditioner more conveniently and more efficiently.
2. Description of the Related Art
Hereinafter, firstly given will be a description of an entire construction of a conventional ceiling-embeded cassette type air conditioner, which will be followed by a description of a conventional turbo fan structure employed in the conventional ceiling-embeded cassette type air conditioner.
FIG. 1 is a bottom view of a conventional ceiling-embeded cassette type air conditioner.
Referring to FIG. 1, the conventional ceiling-embeded cassette type air conditioner has a suction port 11, through which indoor air is introduced, and exhaust ports 12 formed around the suction port 11. In the conventional air conditioner, the indoor air or the external air introduced through the suction port 11 is cooled to have desired temperature and humidity by means of a heat exchanger employed in the air conditioner, and then the cooled air is exhausted through the exhaust ports 12, so as to maintain the indoor air at a more pleasant state.
Hereinafter, the construction and the operation of the conventional ceiling-embeded cassette type air conditioner will be described in detail, with reference to the, internal construction of the conventional ceiling-embeded cassette type air conditioner. FIGS. 2 and 3 are transverse and longitudinal sections of the conventional ceiling-embeded cassette type air conditioner.
Referring to FIGS. 2 and 3, in the ceiling-embeded cassette type air conditioner, the external air is introduced through the suction port 11, which is disposed at a lower portion of the air conditioner, and then the air passes through a bell mouth 16 having a specific shape for decreasing a reduction of pressure, thereby preventing the decrease of efficiency due to the reduction of pressure. Further, the air conditioner includes a driving motor 13 for generating a rotation force and a turbo fan 17 coupled to a rotation shaft of the driving motor 13, so that the indoor air is introduced into the air conditioner by the rotation of the turbo fan 17.
Moreover, the indoor air, which has passed through the suction port 11, the bell mouth 16 and the turbo fan 17 in order, absorbs or discharges heat at a heat exchanger 14, according to the operation state of the ceiling-embeded cassette type air conditioner.
Then, the indoor air, which has passed through the heat exchanger 14 to have desired temperature and humidity, is discharged through the exhaust ports 12 into an indoor space to be air-conditioned. In this case, the indoor air is guided to the exhaust ports 12 by a channel defined according to size and shape of a cabinet 15.
Hereinafter, the construction of the conventional turbo fan 17 as mentioned above will be described in detail, with reference to FIG. 4, which is a perspective view of the turbo fan.
Referring to FIG. 4, the conventional turbo fan includes blades 17a for providing a flowing force, which enables the fluid or the indoor air to be introduced into and exhausted from the air conditioner, a shroud 17b disposed above the blades 17a to prevent the exhausted fluid from being introduced back, and a hub 17c disposed under the blades 17a to fix the blades 17a. 
In the meantime, the turbo fan 17 as described above is usually manufactured by an injection molding. In this case, it is preferred that the turbo fan 17 is integrally formed in the process of the injection molding. However, it is nearly impossible to integrally form the turbo fan 17 due to the structural limitation of the shape of the fan, especially due to the shape of the shroud.
Because of this problem in the above process of manufacturing the turbo fan 17, other manufacturing methods have been utilized in manufacturing the turbo fan 17. That is, in a first alternative method, all elements of the fan but the shroud 17b are integrally formed by the injection molding, and then the separately formed shroud 17b is assembled with the other elements. Otherwise, in a second alternative method, the hub 17c has a reduced outer diameter, so that the entire turbo fan 17 can be integrally formed.
However, in the first alternative method, because the shroud 17b and the other elements are separately manufactured and then assembled with each other, it is not economical in manufacturing time and expense due to such additional labors. Further, in the second alternative method; although it is easier to manufacture the turbo fan 17 due to the reduced outer diameter of the hub 17c, it is problematic that the entire quantity of air blown by the turbo fan 17 is reduced and the operational noise is increased due to the relatively complicated flow of the fluid.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and it is an object of the present invention to provide a turbo fan of a ceiling-embeded cassette type air conditioner, having an improved construction, which not only enable the turbo fan to be manufactured by easier labor but also prevent a decrease of the quantity of blown-air and reduce a generation of noise.
In accordance with one aspect of the present invention, there is provided a turbo fan of a ceiling-embeded cassette type air conditioner, the turbo fan comprising: a shroud for guiding a fluid introduced into the turbo fan; a hub having an outer diameter smaller than an inner diameter of the shroud, so as to facilitate an integral injection molding of the turbo fan; and blades extending between the shroud and the hub and being perpendicular to the shroud and the hub, each of the blades having an inner diameter, which is inclined in such a manner that the inner diameter is decreased from the shroud to the hub, so that a quantity of sucked-air and a static pressure can be increased.
The present invention provides a superior turbo fan of a ceiling-embeded cassette type air conditioner, which not only can be integrally formed by injection molding but also can be manufactured at a reduced manufacturing cost. Further, the present invention can effectively overcome the undesired problem of the prior art due to the modification in dimensions of the turbo fan, thereby providing a turbo fan exhibiting a quantity of blown-air and a static pressure which are the same or increased in comparison with the prior art.